


Thermodynamics of Love

by Anonymous



Category: Big Bang Theory
Genre: Community: sheldon_penny, F/M, Friends to Lovers, Paradox, Saturnalia
Language: English
Status: Completed
Published: 2011-12-21
Updated: 2011-12-21
Packaged: 2017-11-15 06:33:22
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,277
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/524172
Author URL: https://archiveofourown.org/
Summary: <blockquote class="userstuff">
              <p>"Chemistry is involved in the initial attraction, but it is thermodynamics that determines if the relationship will last."</p>
            </blockquote>





	Thermodynamics of Love

**Author's Note:**

  * For [baronessabba](https://archiveofourown.org/gifts?recipient=baronessabba).



> Written for the Paradox (Sheldon/Penny LJ community) Saturnalia Exchange 2011.  
> This was the ficlet accompanying the fanmix, which you can find at (http://sheldon-penny.livejournal.com/1363686.html)

_"Chemistry is involved in the initial attraction, but it is thermodynamics that determines if the relationship will last." – Wild Bob, Internet writer._

* * *

_C.P. Snow's First Law of Thermodynamics: You cannot win._

* * *

Penny and Leonard. They've done their on-off relationship thing for the past couple of years. Like a sitcom couple. And if you'd asked her,  _Why?_ —well, before today she might've told you:  _Because we kept finding our way back to each other, and we didn't want to be apart._

Today, she'll concede the other truth, the one that has remained unspoken in her heart for months:  _We just couldn't stay together, no matter how hard we tried—because we don't fit._

Two people cannot continue an on-off relationship indefinitely. Eventually, the switch stops at one state or the other.

Today, she breaks up with Leonard for the last time.

* * *

_[He put it on me, I put it on,_  
 _Like there was nothing wrong._  
 _It didn't fit,_  
 _It wasn't right._  
 _I didn't feel_  
 _The fairytale feeling, no._  
 _Am I a stupid girl  
_ _For even dreaming that I could?]_

* * *

(Several months later…)

Penny and Sheldon. After knowing him all these years, it's easy to forget certain things—such as the afternoon they'd first met. Those small, undeniable sparks of…something. The fact that she'd almostkindofmaybe started to flirt with him, until he'd opened his mouth and spoken Sheldon.

In another universe, they might've stayed un-remembered and that would've been that.

In this universe, they were driving home from the Cheesecake Factory on another seemingly ordinary evening.

Howard and his "missus" had gone to visit his mother, and Amy, Raj and Leonard off to participate in that oft-talked of neuro-something experiment to cure Raj's women-triggered muteness.  
It was just her and Sheldon, alone in her car. Arguing over her check engine light for the zillionth instance.  _Just like old times_ , she thinks affectionately, and a little wistfully.

She turns her head to snap her usual retort at him—that's when something  _new_ happens.

_[As we were driving_  
 _You turned your head around and looked right at me_  
 _You couldn't see the road and it was scaring me-]_

"You're beautiful when you're crazy," observes Sheldon aloud, almost matter-of-factly. Startled, her gaze leaps to meet his, and she sees in his eyes something that's never been present before.

Her confusion shows on her face— she knows it because she's looking at him so intensely that she sees herself mirrored in those hard blue depths—and oh, it all comes rushing back in a sharp, sudden lash of sensation.

She remembers.

* * *

What had happened in the car earlier with Penny had completely blindsided him. It'd been an unprecedented moment of weakness on his part, certainly.

_[_ _You might think I don't look_  
 _But deep inside_  
 _in the corner of my mind_  
 _I'm attached to you_  
 _I'm weak]_

Sheldon Cooper has never believed in having ephemeral and transient feelings. The attachment of Friendship is a necessary evil, albeit one he has acknowledged as vital to the stability of his existence. But romantic love—Love is nothing more than a chemical reaction in a brain. That is a fact, and it is unfathomable that millions of human beings (even supposedly intelligent individuals such as Leonard) gamble their emotional well-being on a tenuous romantic connection.

He's never seen the need to conduct experiments on that front—the result of his parents' marriage sufficed to convince him at a young age.

Essentially, Love was not something he'd ever thought to look for, or want. But his utter dismissal of it had transformed it into a dangerous force that has now somehow crippled him. He'd never constructed any shields against  _it_ , having counted on his superior mind and utter absorption in his work to render him impervious.  _A deadly error._ He hadn't recognised it when it slipped into him and started flowering like an invisible parasite.

* * *

_You're beautiful._  She hears his words in her mind _. Beautiful._ Replays them over and over again.

Sheldon thinks she's beautiful.

What did he mean? Why had he said it?

_[_ _Your words in my head_  
 _got me mixed up_  
 _so I turned out the light_  
 _And I don't know how_  
 _to slow it down_  
 _My mind's racing]_

Perhaps it was just an observation. Just Sheldon being matter-of-fact and—what's the word she's looking for here?—objective. An objective observation on his part. Like those computers that judge how beautiful people are by analysing the symmetry of their faces. That must've been what he'd meant.

She's obviously imagining things if she thinks otherwise. His eyes hadn't held longing, or intentions, or desire. It'd been merely a trick of the light, or maybe even just her projecting her loneliness onto him or whatever. It definitely wouldn't have been Sheldon's doing—after all, it's been long established that the guy  _doesn't_ have a deal.

So it's not his fault what her imagination had conjured had paralysed her for a long breathless moment. It's not his fault that his careless observation has wrought havoc on her emotions and her heart, not his fault she's misinterpreting innocent remarks and gestures when she knows better.

It's not his fault that Penny can't stop thinking about him tonight.

* * *

_C.P. Snow's Second Law of Thermodynamics: You cannot break even._

* * *

That is, entropy always increases. One cannot revert to the same energy state.

* * *

 

(Several weeks later…)

Since The Incident, he and Penny had by mutual and unspoken agreement set out to behave as if their relationship had never changed. This was done (they silently justified) to spare the delicate feelings of their friends, particularly Leonard and Amy—and of course to protect their friendship with each other.

But this façade they've been enacting for weeks will come to an end, and soon. It is not only mechanical systems that tend towards increasing disorder.

_[_ _Everything will change,_  
 _nothing stays the same_  
 _Oh you're in my veins_  
 _and I cannot get you out_  
 _You're all I taste_  
 _at night inside of my mouth]_

No matter how much Dr Sheldon Cooper would like to be a robot, he isn't and will never be one. No, he is human (though he often likes to pretend otherwise) and as such he has constraints. His body requires oxygen, water, food and sleep to survive. His mind further requires intellectual stimulation and exercise to function optimally. He's discovered a new limitation—he needs her, for his brain to release the elusive chemical reaction that refuses to be triggered by anyone else.

(His heart longs for her.)

* * *

She'd known he would act like nothing had ever happened (and probably to him nothing had, because it was all in her head, remember?) so she does the same. She feigns nonchalance day in and day out for weeks—puts all those acting lessons of hers to good use. They haven't been good for anything else lately.

Her big break  _still_ hadn't come. After all these years in Pasadena, she's still where she first started—stuck in her dead-end waitressing job. Still unfamous, undiscovered, unfound. What if she stays like this—forever lost in the ocean of nameless, hopeless souls? Dammit, she's already overwhelmed as it is—already on the verge of drowning.

She cracks after an unsuccessful audition for a toilet cleaner commercial _. Let's play "How Low Can Penny Go?" She's not even good enough to play a freakin' janitor, that's how low!_

She comes home with makeup streaking her face and tears obscuring her vision. It's storming outside, a big chaotic, thundering mess. Like her life.

Sheldon is checking for mail downstairs when he sees her. Wordlessly he strides to envelop her in his arms, where she collapses like she can't hold herself up anymore. He carries her upstairs, murmuring soothing noises and his embrace tightens as her shuddering sobs soak through his Green Lantern t-shirt.

_[_ _Your warm whispers_  
 _Out of the dark_  
 _they carry my heart]_

He fishes her key out of her pocket and lets them into her apartment. He flicks the light switch and sighs softly. The power's out.

He carries her into her room. Deposits her on her bed. Moves to release her and put some distance between them—but she refuses to let go. Desperately, in the darkness, she clings to him as if he were her one and only lifeline.

He stays.

* * *

They lie together on her bed.

He can smell that faint whiff of strawberries he has subconsciously come to associate with Penny over the years. He can discern her restlessness, the turmoil of her state of mind no doubt arising from the current neurological imbalance of hormones. He can sense a suppressed shiver as chill seeps into her small form—reaching out, he finds he is correct. She was cold.

She can hear his slow, even patterns of inhaling and exhaling. She can make out the murky outline of him on her left, leaning neither towards her nor away. She can feel the heat emanating from his larger, lankier frame at the points of contact where their bodies meet and her skin tingles. He's so warm.

She takes a deep breath. Opens her mouth to speak, but all that comes out is his name.

_[Have you ever needed someone so bad?_  
 _Have you ever wanted someone you just couldn't have?_  
 _Did you ever try so hard that your world just fell apart?]_

He stiffens at the note of desire in her voice, suddenly on edge and far from calm.

Why was this happening  _now_ , when's he never felt that way about her before? He's never felt this way about  _anyone_  before. He contemplates bolting, but his limbs won't obey.

There is a long pause.

Then, he doesn't know who moves first—their mouths meet and the kiss chases all rational thought from his brain. His arms snake around her, and they melt into each other.

* * *

_C.P. Snow's Third Law of Thermodynamics: You cannot get out of the game._

* * *

Afterwards, they don't know what to say. The silence stretches like a gigantic rubber band, and finally it snaps when her patience does.

"Look, I didn't mean what I said just now. Forget it. It was just the heat of the moment, okay?" She babbles, not daring to look at him yet.

She continues: "We need to talk about what just happened." Clutching the sheets around her, she sits up. Runs her fingers through the rat's nest of her hair,  _how did it get so mussed?_ She grimaces. Thank goodness it was still dark— otherwise, she'd look frightful with her raccooned mascara eyes and blotchy, tear-stained cheeks. "But first, I need a shower."

_[_ _Is this the end,  
or where it begins?]_

He's still gazing into pitch black nothingness—her frenzied words during the "heat of the moment" swirling in his mind—when the lights suddenly come on in a blinding flash. "The power's back," she notes as she hastily makes for the bathroom.

He winces at the sound of slamming, stares at the closed door for a few mind-racing seconds. Then he reaches for his clothes.

* * *

(Half an hour later...)

It is an irate Penny who marches up to apartment 4A and performs their established routine for knocking. The door swings open.

"What now, Penny?" he asks, sounding more than a trifle annoyed. He's holding a whiteboard marker in one hand. Over his shoulder she sees he's set up new boards, all of which bear scribbles, calculations and theorems in that familiar handwriting.

"Excuse me?" she can't quite believe her ears. "Hello,  _you're_ the one who ran away before we could have the talk."

"A talk is hardly necessary. You have already expressed your wish to disregard our anomalous sexual encounter."

Her brow furrows, before a wave of understanding crashes over her. "Sheldon, what I said earlier—"

"Everything is fine," he interrupts. "You used me for my body, but I was a willing participant at the time. Guilt is unnecessary, even if you did employ emotional ploys in the process."

"I wasn't pretending!" Desperate for him to understand, she continues: "I meant it. It wasn't the heat of the moment." She can't look at him, not now, so she lets her gaze drop to the floor. "I shouldn't have taken it back."

_[I felt like a fool when I lied and said I was sorry_  
 _But I unapologize,_  
 _I meant every word]_

So absorbed is she in the stitching of her favourite pumps, she misses the quick flicker of hope in his eyes. His face is all firm angles and resolve when he finally reaches out to tilt her chin up.

"Is that true?"

Suddenly, she's breathless and so is he.

_[If you need a lover and a friend  
Baby, I'm in]_

* * *

Often, the chemistry between two people ignites almost immediately—while the underlying attraction burns itself out slowly.

That's not what happened with Sheldon and Penny,  _(obviously.)_

_[Like sunlight, won't you come and lay a ray down?  
You're the one]_

Imagine two people who, on the surface, are very different if you boil them down to generalizations. (She's pretty. He's smart.) They've been friends for years.

And then they get together.

_[Love was kept from me like a secret_  
 _And I swore that I was through_  
 _Until you]_

You might wonder: Will they work out?

(Dr Cooper would tell you that the Thermodynamics of Love theory is hokum. Others will insist that it is a legitimate field of study—because hey, it can analogize the phenomenon and even crank out a prediction for success.

The truth is—no definitive answer is possible.)

_[Love was right in my path, in my grasp  
And me and you belong]_

(But, FYI? They do.)

_fin_


End file.
